The Senate Armed Services Committee (SASC) approved last night its version of the fiscal year 2012 defense authorization bill, which changes the Pentagon’s plans for the F-35 Joint Strike Fighter and Medium Extended Air Defense (MEADS) programs.

SASC Chairman Carl Levin (D-Mich.) plans to brief reporters on the bill today.

He is expected to announce changes to the Pentagon’s plans for Lockheed Martin’s [LMT] F-35. The committee has been critical of over-budget and behind-schedule program. During a May 19 SASC hearing members called for weighing alternatives to the multi-nation fighter aircraft.

The SASC is not expected to propose authorizing funding for the F-35’s alternate engine, General Electric [GE] and Rolls-Royce’s F136.

The Pentagon believes the alternate-engine program is unneeded and too expensive, and terminated it in April shortly after Congress voted to kill FY ‘11 funding for it. Yet supporters, including Levin, argue having competition improves both engines and the long-term cost of keeping or canceling the second engine is nearly the same. The contracting team has offered to spend its own money to continue developing the F136 in FY ‘12.

The House Armed Services Committee (HASC) included language supportive of the second engine in the defense authorization bill the full House approved last month. The legislation includes a provision, which spurred a veto threat from the White House, that would ban the Pentagon from spending money on “performance improvements” to the main F135 engine, made by Pratt & Whitney [UTX], if the defense secretary does not support the alternate engine.

The House bill also would allow General Electric and Rolls-Royce to use the F136 equipment so the contracting team can continue working on the second engine with its own money.

Actual funding for the second engine in FY ’12 is in doubt. The House will take up a budget-setting defense appropriations bill next week that includes no money for it. And Senate Appropriations Committee Chairman Daniel Inouye (D-Hawaii), a supporter, said this week he is pessimistic about including funding in the Senate’s defense appropriations bill.

The SASC also is expected to cut the Pentagon’s $407 million request for MEADS, a three-nation air-defense program the United States may have to pay $800 million to exit in 2014. The Pentagon has not planned to leave the program now because of concerns about hefty contract termination costs.

The prime contractor for MEADS, which has had cost and schedule overruns, is group dubbed MEADS International LLC that includes Lockheed Martin.

MEADS funding would be cut in both the House-passed defense authorization bill and the appropriations legislation it will weigh next week.

The SASC subcommittees marked up their portions of the massive Pentagon policy-setting legislation on Tuesday and Wednesday, and the full committee began working on a combined bill Wednesday. All of the subpanel bill-writing sessions were closed, except the Readiness and Management support subcommittee’s, which was opened to the public on the insistence of Chairwoman Claire McCaskill (D-Mo.)